Does instant dismissal mean I can sack someone on the spot for gross misconduct?

No. Where allegations of gross misconduct arise these should be properly investigated and the individual taken through a fair disciplinary process. If this does not happen then there is a real risk that what would have been a fair dismissal is turned into an unfair dismissal by the lack of process followed. This may mean a school being on the wrong end of an unfair dismissal claim in the Employment Tribunal, even though the individual had committed gross misconduct.

For all disciplinary matters (not just instances of gross misconduct) it is essential that a fair and proper process is followed. The disciplinary process broadly involves:

Conducting a reasonable investigation

D22: Guide to conducting investigation meetings

D4: Invitation to investigation meeting

D5: Invitation to investigation meeting (witnesses)

Inviting the employee to a disciplinary hearing, setting out the allegations against them, and allowing them the opportunity to put forward their version of events. See:

D6: Invitation to disciplinary hearing: potential written warning

D7: Invitation to disciplinary hearing: potential final written warning

D8: Invitation to disciplinary hearing: potential dismissal following previous warnings

D9: Invitation to disciplinary meeting: potential dismissal for gross misconduct

Hold the disciplinary hearing with the employee and see what they have to say, see:

D23: Guide to conducting disciplinary meetings

Decide on an appropriate sanction, confirming this in writing, see:

D12: Informal Management Letter of Advice

D13: Written warning

D14: Final written warning

D15: Dismissal with previous disciplinary warnings

D16: Letter to confirm dismissal – short serving employee

D17: Gross misconduct dismissal

D18: Letter to confirm no further action

If someone exercises their right of appeal then invite them to an appeal hearing, see:

D10: Invitation to appeal meeting

Hold the appeal hearing and decide on an outcome to the appeal:

D24: Guide to conducting appeal meeting

D19: Appeal outcome letter